[SPARK-20120][SQL][FOLLOW-UP] Better way to support spark-sql silent …

…mode.

## What changes were proposed in this pull request?

`spark-sql` silent mode will broken if`SPARK_HOME/jars` missing `kubernetes-model-2.0.0.jar`.
This pr use `sc.setLogLevel (<logLevel>)` to implement silent mode.

## How was this patch tested?

manual tests

```
build/sbt -Phive -Phive-thriftserver package
export SPARK_PREPEND_CLASSES=true
./bin/spark-sql -S
```

Author: Yuming Wang <yumwang@ebay.com>

Closes #20274 from wangyum/SPARK-20120-FOLLOW-UP.

sql/hive-thriftserver/src/main/scala/org/apache/spark/sql/hive/thriftserver/SparkSQLCLIDriver.scala

@@ -35,7 +35,7 @@ import org.apache.hadoop.hive.ql.exec.Utilities
 import org.apache.hadoop.hive.ql.processors._
 import org.apache.hadoop.hive.ql.session.SessionState
 import org.apache.hadoop.security.{Credentials, UserGroupInformation}
-import org.apache.log4j.{Level, Logger}
+import org.apache.log4j.Level
 import org.apache.thrift.transport.TSocket
 
 import org.apache.spark.SparkConf
@@ -300,10 +300,6 @@ private[hive] class SparkSQLCLIDriver extends CliDriver with Logging {
 
   private val console = new SessionState.LogHelper(LOG)
 
-  if (sessionState.getIsSilent) {
-    Logger.getRootLogger.setLevel(Level.WARN)
-  }
-
   private val isRemoteMode = {
     SparkSQLCLIDriver.isRemoteMode(sessionState)
   }
@@ -315,6 +311,9 @@ private[hive] class SparkSQLCLIDriver extends CliDriver with Logging {
   // because the Hive unit tests do not go through the main() code path.
   if (!isRemoteMode) {
     SparkSQLEnv.init()
+    if (sessionState.getIsSilent) {
+      SparkSQLEnv.sparkContext.setLogLevel(Level.WARN.toString)
+    }
   } else {
     // Hive 1.2 + not supported in CLI
     throw new RuntimeException("Remote operations not supported")